Coffee leaf rust outbreak in region is worst in 40 years.

An outbreak of coffee leaf rust is threatening the coffee crop – and the livelihood of the farmers who produce it – in Central America.

The disease, caused by the roya fungus, attacks the leaves of coffee trees and prevents cherries from ripening. The International Coffee Organization said the outbreak is the worst seen since the fungus first appeared in the region in 1976.

Guatamala-based PROMECAFE, an organization working to improve coffee cultivation, predicts that coffee leaf rust will damage crops in Costa Rica, the Dominican Republic, El Salvador, Guatemala, Honduras, Jamaica, Nicaragua and Panama, reducing coffee production by 2.7 million 60-kilogram bags across the region during the current growing season. That’s a 17 percent drop in coffee production over the previous year.

The region is looking at $500 million in lost revenue, with Honduras and Guatemala facing the biggest losses, worth $230 million and $101 million respectively.

PROMECAFE estimates that almost 374,000 coffee workers will lose their jobs due to the blight. As a result, "increased migratory pressure towards North America is to be expected," the ICO said in a report.

The 2013/2014 growing season will likely be even worse, with coffee production potentially dropping by 50 percent in the region, ICO said.

Central America, excluding Mexico, produces nearly 12 percent of the world’s coffee. The ICO report warned of "significant consequences for consumers of specialty coffee, given the importance of Central America as a source of quality Washed Arabica."

Much of of Central America's coffee is premium quality and consumed in the United States.